A-B-X Test refers to that method of comparing a change in a component or sound quality when three audio sources are available. A and B are the original source and the original source with some modification to the signal path or sound quality.
More correctly termed absolute polarity, absolute phase describes a situation in which the phase remains constant throughout a signal path compared to a reference. In real situations, absolute phase means that the + and – polarity of a system are maintained from beginning to end.
A-440 or A440 reffers to the note A, tuned to 440 Hz. A-440 is the standard tuning pitch for most Western music and it is also known as the Stuttgart pitch.
Digital Audio Tape or simply put, DAT, is a signal recording and playback standard medium. DAT was developed by Sony and introduced in 1987. Digital Audio Tape has become the standard recording and archiving technology in professional recording environments for master recordings. The technology is based on video recorders and the 4 mm tape and also the rotary head configuration is closely similar to 8 mm from Sony.
EIA is the abbreviation Electronic Industries Association. EIA is the United States national association of electronic manufacturers. EIA has developed various industry standards for the interference between data processing machines and data communication equipment. EIA ceased operation in 2011 but the former sectors (TIA – Telecommunications Industry Association, ECA – Electronic Components Association, JEDEC, CEA – Consumer Electronics Association, GEIA – Government Electronics and Information Technology Association – TechAmerica) continue to serve the constituencies of EIA.